<template>
    <div class="app-container">
        <h2 style="text-align: center;">发布新课程</h2>
        <el-steps :active="1" process-status="wait" align-center style="marginbottom: 40px;">
            <el-step title="填写课程基本信息" />
            <el-step title="创建课程大纲" />
            <el-step title="提交审核" />
        </el-steps>
        <el-form label-width="120px">
            <el-form-item label="课程标题">
                <el-input v-model="courseInfo.title" placeholder="示例：机器学习项目课：从基础到搭建项目视" />
            </el-form-item>
            <el-form-item label="课程类别">
                <el-select v-model="courseInfo.subjectParentId" placeholder="请选择" @change="subjectLevelOneChanged">
                    <el-option v-for="subject in subjectNestedList" :key="subject.id" :label="subject.title"
                        :value="subject.id" />
                </el-select>
                <el-select v-model="courseInfo.subjectId" placeholder="请选择">
                    <el-option v-for="subject in subSubjectList" :key="subject.value" :label="subject.title"
                        :value="subject.id" />
                </el-select>
            </el-form-item>
            <el-form-item label="课程讲师">
                <el-select v-model="courseInfo.teacherId" placeholder="请选择">
                    <el-option v-for="teacher in teacherList" :key="teacher.id" :label="teacher.name"
                        :value="teacher.id" />
                </el-select>
            </el-form-item>
            <el-form-item label="总课时">
                <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="0" />
            </el-form-item>
            <!-- 课程简介-->
            <el-form-item label="课程简介">
                <tinymce :height="300" v-model="courseInfo.description" />
            </el-form-item>
            <el-form-item label="课程封面">
                <el-upload :show-file-list="false" :on-success="handleAvatarSuccess" :before-upload="beforeAvatarUpload"
                    :action="BASE_API+'/admin/oss/file/upload?host=cover'" class="avatar-uploader">
                    <img :src="courseInfo.cover">
                </el-upload>
            </el-form-item>
            <el-form-item label="课程价格">
                <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="" />
            </el-form-item>
            <el-form-item>
                <el-button :disabled="saveBtnDisabled" type="primary" @click="next">保存并下一步</el-button>
            </el-form-item>
        </el-form>
    </div>
</template>

<script>
import course from '@/api/edu/course'
import teacher from '@/api/edu/teacher'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'
const defaultForm = {
    title: '',
    subjectId: '',
    teacherId: '',
    lessonNum: 0,
    description: '',
    cover: process.env.OSS_PATH + '/cover/default.jpg',
    price: 0
}

export default {
    components: { Tinymce },
    data() {
        return {
            BASE_API: process.env.BASE_API,
            courseInfo: defaultForm,
            subjectNestedList: [],//一级分类列表
            subSubjectList: [],//二级分类列表
            teacherList: [], // 讲师列表
            saveBtnDisabled: false // 保存按钮是否禁用
        }
    },
    watch: {
        $route(to, from) {
            this.init()
        }
    },
    created() {
        this.init()
    },
    methods: {
        updateData() {
            this.saveBtnDisabled = true
            course.updateCourseInfoById(this.courseInfo).then(response => {
                this.$message({
                    type: 'success',
                    message: '修改成功!'
                })
                return response// 将响应结果传递给then
            }).then(response => {
                console.log(response.data)
                this.$router.push({ path: '/edu/course/chapter/' + response.data.courseId }
                )
            }).catch((response) => {
                this.$message({
                    type: 'error',
                    message: '保存失败'
                })
            })
        },
        handleAvatarSuccess(res, file) {
            this.courseInfo.cover = res.data.url
        },
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        init() {
            if (this.$route.params && this.$route.params.id) {
                const id = this.$route.params.id
                this.fetchCourseInfoById(id)
            } else {
                this.courseInfo = { ...defaultForm }
                // 获取讲师列表
                this.initTeacherList()
                this.initSubjectList()
            }
        },

        fetchCourseInfoById(id) {
            course.getCourseInfoById(id).then(responseCourse => {
                this.courseInfo = responseCourse.data.item
                // 初始化分类列表
                subject.getNestedTreeList().then(responseSubject => {
                    this.subjectNestedList = responseSubject.data.items
                    for (let i = 0; i < this.subjectNestedList.length; i++) {
                        if (this.subjectNestedList[i].id === this.courseInfo.subjectParentId) {
                            this.subSubjectList = this.subjectNestedList[i].children
                        }
                    }
                })
                // 获取讲师列表
                this.initTeacherList()
            }).catch((response) => {
                this.$message({
                    type: 'error',
                    message: response.message
                })
            })
        },
        initSubjectList() {
            subject.getNestedTreeList().then(response => {
                this.subjectNestedList = response.data
            })
        },
        subjectLevelOneChanged(value) {
            for (let i = 0; i < this.subjectNestedList.length; i++) {
                if (this.subjectNestedList[i].id === value) {
                    this.subSubjectList = this.subjectNestedList[i].children
                    this.courseInfo.subjectId = ''
                }
            }
        },
        initTeacherList() {
            teacher.getList().then(response => {
                this.teacherList = response.data
            })
        },
        next() {
            this.saveBtnDisabled = true
            if (!this.courseInfo.id) {
                this.saveData()
            } else {
                this.updateData()
            }
        },
        // 保存
        saveData() {
            course.saveCourseInfo(this.courseInfo).then(response => {
                this.$message({
                    type: 'success',
                    message: '保存成功!'
                })
                return response// 将响应结果传递给then
            }).then(response => {
                console.log(response.data)
                this.$router.push({
                    path: '/edu/course/chapter/' + response.data
                })
            }).catch((response) => {
                this.$message({
                    type: 'error',
                    message: response.message
                })
            })
        },
        updateData() {
            this.$router.push({ path: '/edu/course/chapter/1' })
        }
    }
}
</script>

<style scoped>
.tinymce-container {
    line-height: 29px;
}
</style>